Mechanism for transfering flexible work pieces

ABSTRACT

Machines for feeding fabric sheets singly from a stack. Ply disengaging means float lightly with the top ply, as when the ply is indented by a pressing foot, and move laterally to disengage the ply and to nip the top ply. A cam actuatable pawl construction and a slide construction of pick up devices are shown. Rapid movements are shown to enhance the various steps in the cycle.

nited States atent [1 1 Walton et al.

MECHANISM FOR TRANSFERING FLEXIBLE WORK PIECES inventors: Richard R. Walton, Boston; George E. Munchhach, Roslindale, both of Mass.

Assignee: USM Corporation, Boston, Mass.

Filed: June 6, 1972 Appl. No.: 260,305

US. Cl 271/19, 271/10, 271/18 Int. Cl B65h 3/22 Field of Search 271/18, 19, 20, 21, 24,

References Cited UNITED STATES PATENTS 5/1966 Southwell et al. 2'71/19 11/1967 Smith et al 27l/25 X 3,406,961 10/1968 Walton 271/10 3,547,432 12/1970 Herdeg et al. 3,550,932 12/1970 Mason et al.

3,588,091 6/1971 Stone et al 271/19 Primary Examiner-Even C. Blunk Assistant Examiner-Bruce l-l. Stoner, Jr.

Attorney, Agent, or Firm-Carl E. Johnson; Vincent A. White; Richard B. Megley ABSTRACT 15 Claims, 33 Drawing Figures PMENTED MAY 28 I974 SHEET t 0F 5 ERMENTEUW m I 5 m5 m3 SHEEISBF'S Q Hm 411 //d MECHANISM FOR TRANSFERING FLEXIBLE WORK PIECES CROSS REFERENCE TO RELATED APPLICATIONS An application Ser. No. 260,306 is being concurrently filed in the names of Carlton Lutts and James Stewart relating to Ply Separating Mechanism. Also, an application Ser. No. 260,304 (now US. Pat. No. 3,747,919) is being concurrently filed in the names of James Stewart and Carlton Lutts pertaining to Adjustable Work Pick-up Device.

BACKGROUND OF THE INVENTION A need exists for a versatile pick-up device capable of automatically moving successive individual plies of fabric and the like from an external portion, for instance the top, of a stack and preferably without disturbing the position of an adjacent or underlying ply in the stack. The problem is difficult of'solution in reliable manner, and often because there may exist a cleavage of fibers in the interface region.

Some of the prior art patents further elaborating this problem and showing certain techniques, to which reference is made, are US. Pat. Nos. 1,780,195; 3,176,979; 3,253,824; 3,406,961; 3,386,763 and 3,442,505.

SUMMARY OF THE INVENTION In view of the foregoing it is a main object of this invention to provide improved mechanism enabling the above need to be satisfied and in particular to provide, for use in a work transferring machine, an improved pick-up device of simple construction and effective on a range of flaccid sheet material for mechanically seizing and lifting a locality of an external ply of a stack of flexible work pieces without affecting an underply.

Another object of the invention is to provide a novel, yieldable pick-up device adapted to pucker a localized portion of the exposed top sheet of a stack of limp plies, the device including relatively movable means for reliably raising a part of the puckered portion to temporarily seize and fold it on itself during lift-off and transfer.

In accordance with these objects, one aspect of the invention lies in the realization that a dislodging point or points bearing with a total pressure of less than a few ounces upon the exterior or top ply of a stack, and with freedom of the points to lightly float in the normal or perpendicular direction upon the exterior ply both initially and during lateral disengaging motion, can permit single plies of a wide range of consistencies to be removed without disturbing underlying plies of the same or very different consistency. In addition to being prevented from penetrating to the underlying ply by the aggregate resistance (a principle generally shown in Walton 3,406,961), the disengaging elements also avoid pressing upon the outer ply in a manner that would contribute to adhesion or frictional engagement between outer and underlying plies and also allow the contacted portion of the top piece to bulge or pucker or otherwise rise up freely relative to the underlying plies during initial disengaging motion. This combination of features and effects enables a wide variety of thick and thin, dense and loose, stiff and flaccid plies to be removed singly without disturbing the underlying ply.

According to another aspect of the invention a dislodging element mounted to move freely outward in the normal direction to a surface of the stack in response to contact pressure of the exterior ply is combined with a second element adjacent the dislodging element, toward which the latter moves laterally to nip or fold a portion of the top ply and then remove it. Preferably the second element defines a shelf or ledge upon which the ply folds as the disengaging element rises, and preferably means in a terminal portion of the folding motion forces the disengaging element downwardly toward the ledge to grip the ply.

Other features are a cam operated construction of a dislodging element operated, e.g., by a simple movement normal to the stack and a slide-operated construction capable of a snap action movement in the direction parallel to the exterior of the stack, and enabling a low profile device to be presented to a sewing machine or other device receiving the separated ply.

In preferred embodiments of the invention there are featured means to intentionally curve or bulge the stack and outer ply engaged by the dislodging element floats which assists in making the initial separation; means to employ multiple dislodging elements in offset directions for improving separation; and a mechanism for effecting sudden movements of the dislodging element: (a) laterally helping to prevent penetration to the second ply while increasing the hold on the first; (b) normally of the stack for rapid removal when a firm hold on the ply is obtained, and (c) downwardly after removal for deposit of the separated ply with momentum effects assisting in removing the ply from the dislodging element.

A particular feature of the invention resides in the provision of a pick-up device comprising a presser foot having a partly open work engaging perimeter for bulging or puckering an exposed locality of a ply, the foot having a jaw disposed in the perimeter opening and formed with a surface spaced above the work engaging perimeter, and a high friction work disengaging and pinching member yieldingly cooperative with said jaw for clamping a portion of the puckered locality upon the jaw surface.

A further feature of the invention pertains to the provision of a mechanism whereby relative movement of approach of the presser foot and a ply is effective to impart work seizing relative movement between the high friction member and the jaw, and the mounting of the high friction member is such as to enable it to yield heightwise of the stack while closing to pinch the ply on the jaw.

Yet another feature of the invention resides in provision of an adjusting mechanism whereby the initial spacing of the jaw and friction member is made suitable to securing an appropriate nip on the particular material to be seized for transfer.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features of the invention will now be more particularly described in connection with illustrative fabric pick-up devices and with reference to the accompanying drawings, thereof, in which:

FIGS. 1 through 1c are similar sequential views of a diagramatic embodiment of important portions of a fabric transfer machine;

FIGS. 2 through 2d are similar sequential views of an embodiment of important portions of a fabric transfer machine;

FIGS. 3 and 4 illustrate the embodiment of FIG. 2 in successive positions when used to deposit a separated ply upon a surface;

FIG. 5 is a view in side elevation of another preferred embodiment incorporating features of the mechanism illustrated in FIGS. 2 4.

FIGS. 6, 7 and 8 are partially broken-away crosssections, on a larger scale, of the pick-up device of FIG. 5, with the parts in different respective positions, and FIG. 9 is a bottom plan view thereof;

FIG. 10 is a bottom plan view of another preferred embodiment with the parts in different respective positions.

FIG. 11 is a view in side elevation of a portion of an automatic fabric transfer machine employing at least one pick-up device such as the one shown above a stack of work pieces;

FIG. 12 is a schematic plan view of one possible arrangement of a plurality of pick-up devices mounted for instance in the machine of FIG. 11, adjacent pairs of devices being counter rotated for ply separation;

FIG. 13 is similar to FIG. 12, but illustrates an arrangement of two pairs of pick-ups as employed for effecting a different stress pattern aiding in ply separation of a different type of work piece;

FIG. 14 is an enlarged view of a pick-up and ply separating assembly, of the type shown in FIGS. 11 13 in initial work engaging condition;

FIG. 15 is a bottom plan view of the pick-up portion;

FIG. I6 is an axial section showing a pincer of the pick-up device in work seizing position over a stack;

FIG. 17 is a view similar to FIG. 14 but showing the pick-up rotated by its ply separating mechanism;

FIG. I8 is a transverse section taken on the line XVIII-XVIII of FIG. 16 indicating means for limiting the stroke of the pincer, and

FIG. 19 is a detail view of an adjustable detent for controlling friction.

FIGS. 20 and 21 respectively, are a top plan view and side cross-section view of another preferred embodiment of automatic fabric transfer mechanism;

FIG. 22 illustrates use of the mechanism of FIGS. 20 and 21 in delivering a ply of fabric to an awaiting device;

FIGS. 23 23c are similar sequential views of certain portions of the embodiment of FIGS. 20 and 21.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the embodiment of FIGS. 1 to 1c, stack S of plies to be separated comprises different styles and consistencies of shirt material of e.g., 0.010 to 0.025 inch thickness that have been out together in a common pattern. The object of the fabric transfer machine is to automatically separate the outer (in this case top) ply W and feed it to a further operation such as a conveyor sensing machine in a cycle time of 2 seconds, for example, with high dependability of singleness of feed. For clarity of illustration the necessary supporting and moving devices are omitted from the drawing.

FIG. I pictures dislodging element D of a weight of about 1 ounce in an initial position with a series of rigid points P directed toward ply W. These points are sufficiently long and spaced that they have the inherent capability of penetrating multiple plies at least of the thinnest material in stack S, preferably being card cloth points of approximately one-sixteenth inch length.

In FIG. la the element D is lowered to a reference level L and released so that it rests with its weight of 1 ounce, floating upon the top ply while slightly penetrating it.

In FIG. 1b element E has engaged an edge of the stack and caused the portion under element D to convexly curve upwardly, with a tendency to separate the plies in this region. As indicated by the arrow, as the top ply thus puckers or bulges up, element D moves, floating upward with the ply, remaining in penetrating engagement with it.

In FIG. lc element D is removed laterally, dislodging the top ply W.

Sudden reverse movement at the desired time will separate the element D from the ply.

Referring to the embodiment of FIGS. 2 2d a dislodging element D, is again shown with a ply contacting portion comprising rigid points P,. Element D, moves initially from the inoperative position of FIG. 2 relatively downwardly to the operative position of FIG. 2a, in this movement being accompanied by a second element E,. When the disengaging element D,reaches the stack it is free to move upwardly (more generally, in the outward direction normal to the stack) in response to contact pressure with the exterior piece. This enables element D, to be sensitively adjusted in the normal direction to the local portion of the piece being contacted.

It is the intended function that after this movement, the dislodging element D, move laterally toward second element E, to nip a portion of the top piece between the elements, after which the elements are carried away together in a ply removal motion. The present embodiment achieves this general action with specific additional features which in certain instances add to the effectiveness of the operation. Specifically after dislodging element D, reaches the top ply W, and the ply takes control of its level, element E, continues downwardly in the direction of the arrow of FIG. 2a, with a pressing or indenting surface I pressing against the stack and tending to form an increasing bulge B beneath the disengaging element D,. As shown in FIG. 2b element D, rather than resisting this rising motion of the top ply, moves upwardly with it in the direction of the arrow A. The disengaging element is moved laterally from the position of FIG. 2b to that of 20. As the fabric contacted by element D, is moved with it, while the fabric below surface I is held stationary, the fabric in between folds. The additional height attributable to this fold causes element D, to rise further, arrow A, FIG. 20.

In this embodiment element E, is provided with a shelf or ledge e toward and above which the dislodging element moves, arrow A When the fold is positioned over the ledge a, downward force F is applied to the element D,, causing the fold of fabric to be gripped firmly between elements E, and ledge e. The force F is overcome by the thickness of the material gripped, thus the particular spacing finally resulting between the members varies with the particular fabric, but always is appropriate to a firm grip on the fabric ply. Once so gripped elements D, and E, are moved together, e.g., in the direction of arrow R for removal of the top ply. In one preferred form similar devices act similtaneously to remove other portions of the top ply, and the devices are then moved, e.g., as in FIG. 3, until the top ply is positioned above a receiving surface s. For deposit, the assembly is moved rapidly downward toward the surface s from the solid line position of FIG. 4 to suddenly stop at the dotted line position of FIG. 4. Simultaneously element 1), is released from force P so as to be free to move up in response to recovery force of the fabric fold, and at the same time element D moves laterally away from element E These combined motions release the ply and impart sufficient momentum to it that any fabric fibers entangled with elements D, and E, are released and the ply is reliably deposited on surface s. From here the elements return to the position of FIG. 2.

Referring now to the preferred embodiment of FIGS. 5 8 an upstanding pawl 1 defines a cam surface 2 and a tubular member 13 defines a cam actuator surface 3. While a fabric dislodging surface of the pawl rests upon the fabric, lateral movement of the pawl parallel to the plane of the stack face is accomplished by relative movement of the actuator surface normal (perpendicular) to that plane. In this particular embodiment this motion is achieved by vertical movement of FIG. of the elevator carrying stack S upward against the pick-up device. A vertically movable foot 4 of the pick-up device is engaged by the stack in its upward travel and carries the pawl I and its cam surface 2 upwardly relative to actuator surface 3. In the initial position of FIG. 6 the pawl is biased to open position by a light spring 5, and cam surface 2 resides at an angle to the vertical, sloping beneath actuator surface 3. In the embodiment a horizontal pin 6 rigidly secured to an extension of foot 4 extends through the pawl about which the pawl is free to rotate (although alternatively the pawl could be loosely held by retaining parts, etc. Thus as the elevator travels vertically (or more generally, as motion occurs in the normal or perpendicular direction between a stack surface and pick-up device) the pawl while engaged upon the top ply is moved laterally by reaction of its cam surface to the actuator surface 3 as the foot carries the pawl upwardly against it.

It will be seen (and is discussed more fully below) that the pawl and foot may embody all the principles discussed in connection with FIGS. 2 1 and also embodies a particularly advantageous removal feature. Specifically, a means is incorporated responsive to the gripping action of the pick-up device upon a ply of fabric, to move the device upwardly in a rapid or snap motion. This rapidly removes the ply from the stack, and allows the device to be moved, arrow J (FIG. 5), to transfer the ply and return. Thus although actuation depends on movement of the elevator, the remaining portion of the cycle is independent of the relatively slowmoving elevator. The apparatus of FIGS. 5 8 embody this principle with mechanical components for raising and pneumatics for resetting the pick-up device. Specifically, there is associated with a tubular member 13 defining the actuator surface 3, a ramp 7 of 45 slope, the ramp having a detaining notch 8 at its upper end and a stop 9 at its lower end. A horizontally disposed compression spring 10 (FIG. 8) presses a detent member 11 against the ramp, the notch 8 defining a stressed position for the spring and stop 9 a relatively relaxed position.

In the ready position of FIG. 6 detent II engages notch 8 while the pick-up device is open, ready to dislodge a ply. When the pick-up device is closed in plygripping position, any further upward force exerted by the elevator is transmitted through foot 4 and paw] l to tubular member 13. A force condition is reached when the lower edge of the notch 8 is forced past the detent 11, the detent engages ramp 7 and rapidly expands and, acting upon the sloped ramp, rapidly forces the pick-up device upwardly.

For deposit of the ply as described in connection with FIG. 4, and for simultaneously resetting the pawl and foot in its downward ready position, a pneumatic line 17 is provided connected to an appropriate control valve. When air pressure is applied through line 17 pressure is applied through line above the top of the structure M defining the foot. Structure I4 acts as a piston within tubular element 13, the latter acting as a stationary cylinder, and the foot and (when the pin 6 reaches the lower end of the slot 31) the pawl are propelled downwardly. Pawl 4! thus leaves actuator surface 3 and is free to move to its open position. It is propelled to that position by any natural recovery force of the folded ply that has been gripped, by the laterally acting light spring 5, and most assuredly by the sudden jolts it receives during this reset motion. The travel of the shoe structure and the amount the cam surface 2 of the pawl is displaced from the actuator surface 3 is set by an adjustable stop, in this case a threaded rod 19 secured to shoe structure 14, protruding upwardly through the tube to a head 21 which stops upon an end surface 23 of tube 13. (An important feature of this stop is that by adjustment it regulates the amount of rotation permitted the pawl between open and closed positions, which varies the bite of the unit, and enables materials as thick as one-sixteenth inch or more to be picked up by the identical device which can pick up fabrics of 0.010 inch thickness).

The air pressure in line 17 also acts upon piston face 25 to rapidly compress spring 10 and allow return downwardly of the entire assembly of elements including those designated 7, 13, and the within elements I and 4. In this particular embodiment the assembly falls by its own weight within support ring 27 (FIGS. 6 8) and in fact the air pressure through line 15 is not effective to reset the pawl, etc., until hole 29 in the upper part of tube 13 reaches its lower position so as to communicate with line 15.

In this embodiment the pawl has an elongated slot 31 receiving the pin 6 and extending parallel to cam surface 2, giving the pawl (weighing about 1 ounce) the freedom to rest and float upon the top ply as has been described above. Furthermore, during the terminal part of the pick-up motion, when the pawl has moved so that its cam surface is parallel to the bore of tubular member 13, the tube 13 slides down upon the pawl so that the end 37 of the tube engages heel 33 of the pawl, and results in a relative clamping against the shoe. In this embodiment increased clamping occurs as the shoe is moved upward by the elevator until the spring detent is overcome.

FIG. 9 is a bottom plan view of the pick-up portion of the embodiment of FIGS. 5 8 and shows the pawl and points 4' of the shoe 4 toward which the pawl acts.

The embodiment of FIG. 10 can be identical to that of FIGS. 5 9 except that two pawls I and I" are employed, acting upon spaced apart lines of action as shown, in the direction of the arrows. These produce a couple ton the top fabric ply assisting in the separation while the device rests upon the stack face. Instead, two separate pick-up devices having offset lines of action can have the same effect operating on a torque arm which can be readily varied as conditions require.

In the foregoing embodiment of FIGS. 10 an elongated retainer spring 41 protrudes from the side of the foot structure 14 and engages the edge and inner bore of tubular element 13. By appropriate change in the geometry of the spring 41 the resistance to the movement of the foot relative to the tube 13 is adjusted. This adjusts the amount of pressure exerted by the foot upon the stack and hence the amount of indenting or bulging thereof.

We now refer to the preferred embodiment of FIGS. 11 19. v

A machine of the general type for automatically feeding fabric sheets W or the like from the top of a stack S is illustrated and described in US. Letters Pat. No. 3,531,103 issued Sept. 29, I970, in the name of R. R. Walton. The particular pick-off devices therein rely on suction as does the adjustable pick-off means disclosed, for instance, in US. Letters Pat. No. 3,550,932 issued Dec. 29, 1970, in the name of R. C. Mason. The present invention provides a mechanical pick-up device generally designated 10 (FIGS. ll, 14, 16) which is herein illustrated as employed in a fabric transfer machine 12 (FIG. 11) in combination with a fluid pressure operated ply separating mechanism generally designated 14, the assemblage 10, 14 (FIG. 14) being shown by way of example only as adjustably mounted on a movable carrier 16 (FIGS. 11 and 14) as, for instance, in the manner disclosed in the cited Mason Patent. It will be understood that, according to the size, shape, and weight of the work pieces W to be transferred, one or a plurality of the assemblages l0, 14 may be mounted in any selected pattern on the carrier 16 as suggested in FIGS. 12 and 13 or otherwise as needed.

The pick-up device 10 herein claimed may be operated in combination with other ply separating mechanism, as well as the ply separating mechanism 14 claimed in the cited concurrently filed Lutts et al. application. It will be understood the plies W to be transferred may be top, bottom, or otherwise externally exposed.

For detachably and slidably supporting the assemblage 10, 14 a tubular body 18 (FIGS. 14, 17) has a threaded stem at its upper end extending through a slot in the carrier 16 for receiving a thumb nut 20. The body 18 is formed with ports 22, 24 (FIGS. 14 and 17) and a partly helical slot 26 for purposes later explained. Slidable axially in the body 18 is a piston 28 having a radial hole the wall of which is threaded for receiving a cam pin 32 slidably extending through the slot 26. As shown in FIG. 14, the upper portion of the slot 26 is longitudinal and the lower portion extends helically at about 45, relative heightwise and turning movement of the piston 28 being thus limited. A head 34 of the piston is disposed at the lower end of an upper chamber 36 in the body 18 having communication with the port 22, and a lower chamber 38 in the piston communicates with the port 24 via a hole 40 in the wall of the piston 28 when the latter is in its relatively lower position, the hole 40 being effectively closed by the wall of the body 18 when the piston 28 is relatively raised as shown in FIG. l7.

Within the lower end of the piston 28, a cylindrical stem of a presser foot 42 is axially slidable within limits, being secured by a set screw 44 (FIG. 14) extending through a longitudinal slot 46 in the piston and threaded into the stem. As shown in FIGS. 14 16, a work engageable peripheral portion 48 of the presser foot is eccentrically enlarged and circular, and centralized with respect to a diametric slot 50. Secured in this slot by a set screw 52 is a V-shaped tooth 54 having its bevelled faces 56, 56 receding in the slot and extending upwardly to define a shelf portion 58 having an apex slightly above the work engaging surface 48. For cooperating with the presser foot 42 the pick-up device 10 includes a pinch pawl 60. The pawl 60 has pin 62 and slot 64 connection in a heightwise kerf in the presser foot 42, the arrangement being such that a pair of paralled rows of pointed and biased teeth 66 arcuately disposed on the underside of the pawl 60 are respectively movable in their planes to engage the top sheet W in the locality P (FIGS. 14, 16) where it may have been bulged or puckered by the compressive action of the presser foot portion 48 and, by means next explained, gather the localized portion in pinching relation onto the shelf portion 58, as shown in FIG. 16. The slot 64 may have its length as small as the diameter of the pin 62.

Adjustably threaded onto the lower end of the piston 28 is a pinch adjusting ring nut 70 (FIGS. 14 18) having a circular camming lip 72 (FIG. 16). A leaf spring 74 is secured at one end to the pawl 60 and has a free downwardly extending portion engageable with an innerface 76 of the presser foot 42 to urge the pawl towards its open or inoperative position. The spring 74 accordingly yieldingly resists movement of the teeth 66 toward pinching relation with the presser foot 42, and more positive pinching is effected as the lip 72 is relatively lowered to cam the pawl 66 toward the shelf portion 58 by mechanism later explained. The ring nut 70 at 90 spacings is semi-bored as at 76 both radially and longitudinal to provide four alternative positions for mating with a cut-away portion 77 in the piston 28 and thus accommodating a pinch control lock pin 78. It will be understood that the pin 78 is detachable and insertable to lock the ring nut in the particular 90 rotational setting affording best results for the heightwise position of the lip 72, a relatively higher lip generally permitting a wider initial nipping position for pinching thicker or more substantial work pieces. Viewed alternatively, for dealing with very thin sheet material, refined adjustment by means of the ring nut insures that only a single ply will be seized.

Preferably, the degree of friction between the presser foot stem and the piston 28 is adjustably controlled better to accommodate different types of work pieces W and insure that the top piece will be suitably puckered about the shelf portion 58, for instance as illustrated at P (FIGS. 14 and 16). To this end, and as herein shown in FIG. 19, for instance, a spring pressed ball detent 80 engaging the interior wall of the piston 28 is nested in the presser foot stem and backed by an adjustable set screw 82. It will be understood that threading the screw 82 inwardly to increase friction will cause the presser foot 42 to react harder on the stack S before relatively yielding upwardly.

In operation of the fabric transferring machine 12 relative movement of approach of the stack S and the pick-up device 10 is in this case effected by raising the stack by a cyclical elevator mechanism 33 (FIG. 11) until a pneumatic sensor in the form of a tube 34 (FIGS. 14 and 16) signals for stack lowering (following a time delay) after the top ply has been initially engaged as shown in FIG. 14. The chamber 38 is then a open to exhaust, and a low pressure (roughly on the avfixed in a collar 96 secured on the piston 23. The tube 34 is disposed to be blocked at its lower end by the presser foot 42 approaching an upper limit as shown in FIG. 16. Air flow downwardly in a flexible supply line 92 connected to the tube 84 is thus stopped and the resultant signal, in addition to stopping elevation of the stack S, also signals for operation of the ply separating mechanism I4 by dumping pressure from the chamber 36 whereupon the spring 86 at once causes lifting and rotation of the piston 26 and likewise of the presser foot 42 for effecting separation of the picked-up top ply. The upward displacement of the sensor tube 84 is against resistance of a return spring 94.

Reverting to a more detailed consideration of operation of the pick-up device 10, which functions prior to rotation about a vertical axis, as the stack S is elevated the presser foot 42 yields upwardly with resistance as suitably selected to compress and thereby bulge or pucker a locality of the top ply W as at I. eccentrically of the piston 28 thus causing an irregular and somewhat annular wave in the top sheet immediately beneath the open pincer teeth 66 to come into engagement therewith at each side of the apex of the shelf 58. The pawl 66, as the presser foot is relatively raised in the piston 28, is cammed by the lip 72 to pinch the puckered portion upon the shelf 58. In this action the rows of teeth 66 first urge the work against the V-tooth point and then rise further as allowed by the slot 64 to move past that point on its opposite sides to hold a small work portion folded and clamped upon itself. Only the single top ply is thus pinched.

Upon actuation by the spring 86 as aforesaid, the piston 28 is raised following pick-up and, by means of the cam pin 32 of the ply separating mechanism 14, rotated clockwise as viewed from above and shown in FIG. 17. Thus at one or more selected localities the seized work is subjected to localized twisting to disrupt cleavage of interfacial fibers. It will be understood that, as typically shown in FIGS. 12 and 13, certain pairs of the assemblies It) 14 may provide twisting in opposite direction, their slots 26 in such cases being'oppositely inclined helically in order to provide desired stress patterns such as suggested in FIGS. 12 and 13 considered most effective for insuring that an underply is not disturbed as the top ply alone is separated and relatively raised.

The assemblies 14 are now jointly moved by the carrier 16 to laterally position the work over a selected delivery position. At the end of this lateral feeding stroke a switch (not shown) is actuated to pressurize the upper chamber 36 to a degree considerably higher than previously. This forces the piston 28 downward against influence of the spring 86 to return the cam pin 32 to the bottom of its slot 26. The downward move ment of the piston and its resultant rotation to unstress the ply then being carried open the port 40 to let air under pressure through the port 24 and into the chamber 33. As a consequence the presser foot 42 is abruptly forced downwardly to enable the pawl 60 to be freed by inertia and thus causes the supported top ply to be released for delivery.

In the course of the return trip of the carrier 16 from the work delivery position to the pick-up position above the stack for repeating the cycle, the chamber 38 is exhausted and the chamber 36 is again provided with its lower pressure.

In the embodiment of FIGS. 20 230 a movable arm 101 carries a low profile pick-up device from the ply dislodging position shown in FIG. 21 into a restricted space 1116 illustrated in FIG. 22 such as offered by sewing machines and other ply-receiving equipment.

Arm Itlll carries base 103 against the stack face with pressure sufficient to dent the stack as shown in FIG. 23 and create a relative bulge B beyond its end. A slide member 1105 is slidably mounted on base 103, e.g., by means of an elongated slot 107 in member and a pair of guide posts I09 and 111 mounted on the base, spaced a distance less than the length of the slot to define the length of permitted travel. The member is held against the base by light compression springs lll9and llIl, thus givingthe end of member 105 freedom to rise under light pressure, e.g., less than one or a few ounces. Member 105 is urged to the left by tension spring 115, but is restrained as in FIG. 23 by a catch member 117, here formed by a block having a height of approximately l cm and a length of 6cm. A shoulder I19 of the slide member engages the rightward shoulder of the block, restraining member 105 from springing to the left.

The slide member I05 carries on its rightward end a fabric dislodging element 121, in this embodiment comprising rigid teeth 123 of metal card cloth bent in an arc with a lower portion having a horizontal tangent. In this embodiment as in the others the card cloth may be of any of a number of varieties available, for instance, from Ashworth Brothers in Fall River, Mass, and here, as in the other embodiments, the tiny teeth 123 or prongs are angled downwardly and in the direction of lateral movement of the dislodging element in its dislodging direction. Leftward, in the path of travel of the element 121, the upper surface of base I03 is sloped upward at 125 providing a shelf or ledge over which the element 121 travels. The curve of element 121 disposes in particular the prongs 123 near horizontal tangency for contact with the top ply, there being e.g., 5 prong rows in the slide direction.

In operation, as the base 103 is pressed against the ply (FIG. 23) the points engage the top ply. Further downward movement of the base 163 from the position in FIG. 23 to the position in FIG. 23a, results in the dislodging element floating higher with the portion of the top ply being contacted, this resulting in shoulder 119 (or a roller if lower friction is desired) riding up on shoulder I17 until it clears as shown in FIG. 23a. Immediately, the slide member 105 is snapped to the left by the spring I15, the shoulder 119 being prevented from lowering by the block 117, over the length of the block. Thus in an action like that described previously, the top ply is dislodged to the left and folds over the ledge 125, FIG. 23b. When the end of block 117 is reached, the upward restraint of the block is removed and the restraining element may lower in a gripping action upon the folded ply, FIG. 23c. Thereupon arm 101 is lifted to the dotted line position shown in FIG. 21 for removing the ply or the grasped portions from the stack and then it is moved to a deposit position as illustrated in FIG. 22. At this point the ply is deposited by pneumatics and a jostling of the dislodging element accomplished by simply returning it to open position. For this purpose compressed air is introduced through line 131 to force piston 133 to the right, carrying with it slide member 105. As the leading part 120 of the slide strikes the retaining block 117 it is bumped upwardly as it opens, helping to jerk the points free of the ply and helping to straighten the temporary fold that was formed.

The sudden lateral movement of the dislodging element by the pressure of the top ply has the simultaneous benefits of helping to prevent penetration to the second ply and increasing the hold upon the first ply.

The principles herein described are useful in many embodiments and in conjunction with additional features. Thus, in each instance where the dislodging element is employed to draw a margin of a ply back over the stack face, away from an edge, it becomes possible to contact the underlying ply and stack with a retaining element prior to further raising the top ply. The device here described is readily combined with other devices and surfaces helpful to removing the ply once the firm grasp of the present invention is achieved.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

l. A machine for feeding fabric sheets singly from a stack including stack support means and sheet removal means, the latter including a dislodging element, means for positioning said dislodging element and a cooperative stack engageable foot in operative relation at the exterior of the stack, means permitting said dislodging element to move freely outwardly from the stack in the direction normal to its external surface in response to contact pressure of a portion of an exterior fabric sheet with said element, means for moving said dislodging element laterally of said fabric sheet to dislodge siad portion of said sheet, a control means operable upon a predetermined free outward movement of said dislodging element from the stack to initiate said lateral movement of said dislodging element into nipping relation to said foot, and means cooperating with said dislodging element for removing said sheet from said stack.

2. In a machine for transferring single plies of flexible sheet material from the exterior of a stack and including a work support for the stack, a carrier mounted above the support for movement laterally thereof, and means for causing relative movement of approach between the work support and the carrier, at least one pick-up device supported by the carrier, said device comprising a presser foot yieldable heightwise of the stack and having a portion adapted to bulge or pucker a locality of an exterior ply of the stack upon engagement therewith, a high friction member cooperative with said presser foot portion, and mechanism responsive to the heightwise yielding movement of the presser foot for causing the high friction member to move laterally of the stack and pinch said locality against said presser foot portion.

3. A machine as in claim 2 wherein the presser foot has a work engaging surface for puckering a top ply locality, a pointed tooth secured to the presser foot is formed with a shelf spaced slightly above said presser foot work engaging surface, and said friction member is formed with pointed elements and pivotally supported for urging the puckered locality to be moved over the pointed tooth and pinch against said shelf.

4. A pick-up device for seizing single plies of flaccid workpieces in a stack comprising a presser foot having a work engaging slotted portion for puckering an exposed locality of a top ply, means for yieldably mounting the presser foot, a jaw disposed within the slotted portion and formed with a surface spaced above the work engaging perimeter of said slotted portion from the top ply of the stack, a pincer means movably carried by the presser foot for movement into and out of cooperative ply seizing relation with said jaw surface, and mechanism for causing the pincer means to coact with the jaw surface upon a portion of the locality puckered by said presser foot.

5. A device as in claim 4 wherein said jaw is formed with an apex, and said pawl is provided with spaced rows of teeth disposed for relative movement one on each side of the apex to urge a top ply thereagainst in pinching relation.

6. A device as in claim 4 wherein the pincer means is a pivotal pawl, said mechanism for causing the pincer means and the jaw surface to coact includes a cam relatively movable heightwise of the stack and engageable with one of the pawl and the presser foot, and mechanism for adjustably controlling friction between the foot and its mounting means to insure puckering of the top ply prior to pinching engagement by the pawl.

7. In a machine for transferring single plies of fabric and the like from the top of a stack and including a laterally movable carrier above the stack, the combination of at least one pick-up device, and means mounting the device on said carrier, said device comprising a foot yieldably engageable with the top ply to pucker a locality thereof, a V-shaped shelf portion secured adjacent to the bottom of said foot, a toothed member yieldable heightwise of the stack and carried by the foot for movement transversely thereof to pinch a portion of the puckered locality on said shelf portion, and mechanism responsive to movement of the foot relative to the carrier for forcing the member toward the shelf portion to fold and squeeze the puckered locality thereon.

8. A pick-up device comprising a presser foot having a work engaging surface and a stem eccentrically upstanding therefrom, a pointed jaw secured in a recess in said surface and having a shelf portion adjacent thereto, a wedge-shaped pawl pivotally supported on said stem and having convexly disposed teeth arranged in at least one row, and cam mechanism for engaging a surface of said wedge-shaped pawl to move its teeth onto said shelf portion to pinch a localized portion of the work on said shelf portion.

9. A machine for feeding fabric sheets singly from a stack comprising stack support means and sheet removal means, the latter including a work dislodging element in the form of an upstanding pawl supported on a movable piston-cylinder device and having a camming surface, a second work engageable element supported by the device for cooperating with said pawl, a cam operator surface formed on said device and arranged during relative movement of the device and the stack to cause lateral closing movement of the dislodging element to nip a portion of the top fabric against said second element, means for moving the pistoncylinder device to remove the nipped fabric sheet from the stack, and mechanism for controlling pressure fluid to said device to separate said elements and release the transferred sheet.

- and having a camming surface, a stack. indenting foot supported by the carrier adjacent to said pawl, and a cam operator surface associated with said foot, said foot being adapted to be engaged by the upwardly moving stack on the elevator to cause the cam operator surface to act on said camming surface and thereby laterally move said pawl into work nipping relation to said foot.

11. A machine for feeding fabric pieces singly from a stack, comprising means for supporting the stack, and piece removal means operable above said stack supporting means, said piece removal means including a carrier, an upstanding work dislodging pawl pivotally and yieldably supported on the carrier and having a camming surface, a foot portion of the carrier being disposed for engagement with a top fabric piece adjacent to a work engageable portion of the pawl, means mounting the carrier for relatively movement heightwise of the stack and into engagement with said camming surface to cause the pawl to nip the portion of said top piece cooperatively with said foot portion, and mechanism for supporting the carrier and substantially movable heightwise of the stack to raise the pawl and foot together with the nipped workpiece.

12. A machine for feeding fabric sheets singly from a stack including stack supporting means and sheet removal means, the latter comprising a dislodging element, means for positioning the dislodging element in operative relation in the exterior of the stack, means permitting said dislodging element to move freely from the stack in a direction normal to its exterior in response to contact pressure of an external portion of an exterior sheet, means for moving said dislodging ele ment to dislodge said portion of the sheet, a nipping member cooperative with said element for removing the sheet from the stack, a spring urged slide movable parallel to an external face of the stack, and a releasable catch means for said slide adapted to carry the dislodging element and said nipping member and releasable in response to free normal movement of the dislodging element to permit the latter to cooperate with the nipping member in removing the nipped sheet.

13. The machine of claim 12 wherein the dislodging element comprises at least one pointed member, and said catch means is adapted to release said slide upon work contact pressure less than required for penetration of said pointed member to the underlying fabric sheet, whereby the dislodging element and nipping member are raised from the stack with snap action.

14. In a machine for transferring single plies of flexible sheet material from the exterior of a stack and including a work support for the stack, a carrier mounted above the support, and means for causing relative movement of approach between the work support and the carrier, at least one pick-up device supported by the carrier, said device comprising a presser foot yieldable heightwise of the stack and having a portion adapted to bulge or pucker a locality of an exterior ply of the stack upon engagement therewith, a high friction member cooperative with said presser foot portion, and mechanism responsive to the heightwise yielding movement of the presser foot for causing the high friction member to move laterally of the stack and pinch said locality against said presser foot portion.

15. A machine as set forth in claim 14 wherein said high friction member has a camming surface, and said mechanism responsive to said heightwise movement of the presser foot comprising a cam operator surface arranged, during yielding movement of said presser foot to cause lateral movement of said presser foot member. =l= 

1. A machine for feeding fabric sheets singly from a stack including stack support means and sheet removal means, the latter including a dislodging element, means for positioning said dislodging element and a cooperative stack engageable foot in operative relation at the exterior of the stack, means permitting said dislodging element to move freely outwardly from the stack in the direction normal to its external surface in response to contact pressure of a portion of an exterior fabric sheet with said element, means for moving said dislodging element laterally of said fabric sheet to dislodge siad portion of said sheet, a control means operable upon a predetermined free outward movement of said dislodging element from the stack to initiate said lateral movement of said dislodging element into nipping relation to said foot, and means cooperating with said dislodging element for removing said sheet from said stack.
 2. In a machine for transferring single plies of flexible sheet material from the exterior of a stack and including a work support for the stack, a carrier mounted above the support for movement laterally thereof, and means for causing relative movement of approach between the work support and the carrier, at least one pick-up device supported by the carrier, said device comprising a presser foot yieldable heightwise of the stack and having a portion adapted to bulge or pucker a locality of an exterior ply of the stack upon engagement therewith, a high friction member cooperative with said presser foot portion, and mechanism responsive to the heightwise yielding movement of the presser foot for causing the high friction member to move laterally of the stack and pinch said locality against said presser foot portion.
 3. A machine as in claim 2 wherein the presser foot has a work engaging surface for puckering a top ply locality, a pointed tooth secured to the presser foot is formed with a shelf spaced slightly above said presser foot work engaging surface, and said friction member is formed with pointed elements and pivotally supported for urging the puckered locality to be moved over the pointed tooth and pinch against said shelf.
 4. A pick-up device for seizing single plies of flaccid workpieces in a stack comprising a presser foot having a work engaging slotted portion for puckering an exposed locality of a top ply, means for yieldably mounting the presser foot, a jaw disposed within the slotted portion and formed with a surface spaced above the Work engaging perimeter of said slotted portion from the top ply of the stack, a pincer means movably carried by the presser foot for movement into and out of cooperative ply seizing relation with said jaw surface, and mechanism for causing the pincer means to coact with the jaw surface upon a portion of the locality puckered by said presser foot.
 5. A device as in claim 4 wherein said jaw is formed with an apex, and said pawl is provided with spaced rows of teeth disposed for relative movement one on each side of the apex to urge a top ply thereagainst in pinching relation.
 6. A device as in claim 4 wherein the pincer means is a pivotal pawl, said mechanism for causing the pincer means and the jaw surface to coact includes a cam relatively movable heightwise of the stack and engageable with one of the pawl and the presser foot, and mechanism for adjustably controlling friction between the foot and its mounting means to insure puckering of the top ply prior to pinching engagement by the pawl.
 7. In a machine for transferring single plies of fabric and the like from the top of a stack and including a laterally movable carrier above the stack, the combination of at least one pick-up device, and means mounting the device on said carrier, said device comprising a foot yieldably engageable with the top ply to pucker a locality thereof, a V-shaped shelf portion secured adjacent to the bottom of said foot, a toothed member yieldable heightwise of the stack and carried by the foot for movement transversely thereof to pinch a portion of the puckered locality on said shelf portion, and mechanism responsive to movement of the foot relative to the carrier for forcing the member toward the shelf portion to fold and squeeze the puckered locality thereon.
 8. A pick-up device comprising a presser foot having a work engaging surface and a stem eccentrically upstanding therefrom, a pointed jaw secured in a recess in said surface and having a shelf portion adjacent thereto, a wedge-shaped pawl pivotally supported on said stem and having convexly disposed teeth arranged in at least one row, and cam mechanism for engaging a surface of said wedge-shaped pawl to move its teeth onto said shelf portion to pinch a localized portion of the work on said shelf portion.
 9. A machine for feeding fabric sheets singly from a stack comprising stack support means and sheet removal means, the latter including a work dislodging element in the form of an upstanding pawl supported on a movable piston-cylinder device and having a camming surface, a second work engageable element supported by the device for cooperating with said pawl, a cam operator surface formed on said device and arranged during relative movement of the device and the stack to cause lateral closing movement of the dislodging element to nip a portion of the top fabric against said second element, means for moving the piston-cylinder device to remove the nipped fabric sheet from the stack, and mechanism for controlling pressure fluid to said device to separate said elements and release the transferred sheet.
 10. A machine for feeding fabric sheets singly from a stack, comprising an elevator for moving the stack upwardly, and sheet removal means above the elevator including a dislodging element in the form of an upstanding pawl, said pawl being supported on a carrier and having a camming surface, a stack indenting foot supported by the carrier adjacent to said pawl, and a cam operator surface associated with said foot, said foot being adapted to be engaged by the upwardly moving stack on the elevator to cause the cam operator surface to act on said camming surface and thereby laterally move said pawl into work nipping relation to said foot.
 11. A machine for feeding fabric pieces singly from a stack, comprising means for supporting the stack, and piece removal means operable above said stack supporting means, said piece removal means including a carrier, an upstanding work dislodging pawl pivotally and yieldably supported on the carRier and having a camming surface, a foot portion of the carrier being disposed for engagement with a top fabric piece adjacent to a work engageable portion of the pawl, means mounting the carrier for relatively movement heightwise of the stack and into engagement with said camming surface to cause the pawl to nip the portion of said top piece cooperatively with said foot portion, and mechanism for supporting the carrier and substantially movable heightwise of the stack to raise the pawl and foot together with the nipped work piece.
 12. A machine for feeding fabric sheets singly from a stack including stack supporting means and sheet removal means, the latter comprising a dislodging element, means for positioning the dislodging element in operative relation in the exterior of the stack, means permitting said dislodging element to move freely from the stack in a direction normal to its exterior in response to contact pressure of an external portion of an exterior sheet, means for moving said dislodging element to dislodge said portion of the sheet, a nipping member cooperative with said element for removing the sheet from the stack, a spring urged slide movable parallel to an external face of the stack, and a releasable catch means for said slide adapted to carry the dislodging element and said nipping member and releasable in response to free normal movement of the dislodging element to permit the latter to cooperate with the nipping member in removing the nipped sheet.
 13. The machine of claim 12 wherein the dislodging element comprises at least one pointed member, and said catch means is adapted to release said slide upon work contact pressure less than required for penetration of said pointed member to the underlying fabric sheet, whereby the dislodging element and nipping member are raised from the stack with snap action.
 14. In a machine for transferring single plies of flexible sheet material from the exterior of a stack and including a work support for the stack, a carrier mounted above the support, and means for causing relative movement of approach between the work support and the carrier, at least one pick-up device supported by the carrier, said device comprising a presser foot yieldable heightwise of the stack and having a portion adapted to bulge or pucker a locality of an exterior ply of the stack upon engagement therewith, a high friction member cooperative with said presser foot portion, and mechanism responsive to the heightwise yielding movement of the presser foot for causing the high friction member to move laterally of the stack and pinch said locality against said presser foot portion.
 15. A machine as set forth in claim 14 wherein said high friction member has a camming surface, and said mechanism responsive to said heightwise movement of the presser foot comprising a cam operator surface arranged, during yielding movement of said presser foot to cause lateral movement of said presser foot member. 